How to construct a punnett square

    Cards (5)

    • Our genes are inherited from our parents, and the different combinations of these genes make us unique
    • Genetic inheritance controls the characteristics of all living things
    • Genetic inheritance includes:
      • Carrying out a genetic cross
      • How to construct Punnett squares
      • Examples of genetic crosses
      • Sex determination
      • Inherited disorders
      • Limits of genetic testing
      • Family trees
      • Understanding of genetics including Mendel's work
    • Method to construct Punnett squares:
      • Determine the parental genotypes - the allele combinations for the male and female
      • Split the alleles for each parental type and add them into the Punnett square around the edges
      • Work out the new possible genetic combinations inside the Punnett square
      • Use this information to answer questions related to allele combinations in the offspring, calculate probability ratios, or determine the phenotypes of the offspring
    • Example:
      • Inheritance of fur colour in mice is controlled by a single gene
      • White fur is recessive, grey fur is dominant
      • When two mice that are heterozygous for the fur colour gene mate, there is a 75% probability that the offspring will have grey fur and a 25% probability that the offspring will have white fur